The limit was being reset per-thread, which isn't how it was intended or
documented. Add test to confirm the limit is more-or-less respected.
R=mark@chromium.org
BUG=crashpad:111
Change-Id: Ifae9f1ce2afcc2d6c6832db46f9b5c36adb35b42
Reviewed-on: https://chromium-review.googlesource.com/346131
Reviewed-by: Mark Mentovai <mark@chromium.org>